Scientists can't say that global warming caused hurricane Irene or Katia or tropical storm Lee. But they can say that global warming produces the conditions that lead to hurricanes. Americans should be reducing greenhouse gas emissions and preparing for severe weather to come.
Like many people, I spent the last weekend in August mesmerized by the steady progress of hurricane Irene as she followed the script so carefully laid out by the National Weather Service’s Hurricane Tracking Center. Not too long ago, hurricane prediction was more like trying to guess the direction that an improvisational theatrical performance was going to take. However, as the science has improved, some of the apparent spontaneity of hurricanes has disappeared.
Nevertheless, there remain questions that scientists cannot and never will be able to answer with certainty. One of these unanswerable questions, literally a billion-dollar question, is the following: Is global climate change responsible for a given hurricane or any other weather disaster?
Scientific answers to this question can be either simple or complex. The simple answer is that we cannot know with absolute certainty that global climate change caused any particular weather event. However, the science is improving to the point that we can begin to start assigning probabilities to such events as the Earth’s climate warms in response to humanity’s continuing emissions of greenhouse gases.